The following discussion is intended to facilitate the understanding of the invention, but is not intended nor admitted to be prior art to the invention.
Obesity is a public health problem that is serious, widespread, and increasing. In the United States, 20 percent of the population is obese; in Europe, a slightly lower percentage is obese (Friedman (2000) Nature 404:632-634). Obesity is associated with increased risk of hypertension, cardiovascular disease, diabetes, and cancer as well as respiratory complications and osteoarthritis (Kopelman (2000) Nature 404:635-643). Even modest weight loss ameliorates these associated conditions.
While still acknowledging that lifestyle factors including environment, diet, age and exercise play a role in obesity, twin studies, analyses of familial aggregation, and adoption studies all indicate that obesity is largely the result of genetic factors (Harsh et al (2000) Nature 404:644-651). In agreement with these studies, is the fact that an increasing number of metabolic-related genes are being identified. Some of the more extensively studied genes include those encoding leptin (ob) and its receptor (db), pro-opiomelanocortin (Poinc), melanocortin-4-receptor (Mc4r), agouti protein (Ay), carboxypeptidase E (fat), 5-hydroxytryptamine receptor 2C (Htr2c), nescient basic helix-loop-helix 2 (Nhlh2), prohormone convertase 1 (PCSK1), and tubby protein (tubby) (rev'd in Barsh et al (2000) Nature 404:644-651).